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checkpatch: forbid implied-barrier I/O functions. 

Forbid read[bwl], write[bwl], in[bwl], and out[bwl], as they
contain a 'stealth barrier' which can harm performance.
Developers are expected to call appropriate __raw_* or *_relaxed
APIs and manage barriers explicitly.

Change-Id: Ie4da221c91a0505917199db9e2fdb704c3e47d44
Signed-off-by: Gregory Bean <gbean@codeaurora.org>
(cherry picked from commit 032fd4ba09e195d9913c08f460130da9905936ef)
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
This commit is contained in:
Gregory Bean 2011-05-02 13:50:35 -07:00 committed by Stepan Moskovchenko
parent 976e4e20d5
commit 1c82fe3903
1 changed files with 20 additions and 0 deletions
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20
scripts/checkpatch.pl
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@ -4515,6 +4515,26 @@ sub process {
$herecurr);
}
# read[bwl] & write[bwl] use too many barriers, use the _relaxed variants
if ($line =~ /\b((?:read|write)[bwl])\b/) {
ERROR("NON_RELAXED_IO",
"Use of $1 is deprecated: use $1_relaxed\n\t" .
"with appropriate memory barriers instead.\n" .
$herecurr);
}
# likewise, in/out[bwl] should be __raw_read/write[bwl]...
if ($line =~ /\b((in|out)([bwl]))\b/) {
my ($all, $pref, $suf) = ($1, $2, $3);
$pref =~ s/in/read/;
$pref =~ s/out/write/;
ERROR("NON_RELAXED_IO",
"Use of $all is deprecated: use " .
"__raw_$pref$suf\n\t" .
"with appropriate memory barriers instead.\n" .
$herecurr);
}
# warn about #if 0
if ($line =~ /^.\s*\#\s*if\s+0\b/) {
WARN("IF_0",